We did a lab where we had four aluminium pendulums made with differenly shaped e

Question

We did a lab where we had four aluminium pendulums made with differenly shaped ends. We had a strong magnet set up so that the pendulum can swing through a gap between the poles. We then looked at how the different pendulums moved through the magnet.

Consider the aluminum pendulum in the induction lab. Suppose the aluminum pieces used were cooled to liquid nitrogen temperatures so that their resistance is reduced. The oscillations will be further damped when the remaining conditions remain the same because

options:

eddy current is larger.

induced voltage is smaller.

eddy current is smaller.

induced voltage is larger.

eddy current is larger.

induced voltage is smaller.

eddy current is smaller.

induced voltage is larger.

Explanation / Answer

Answer is Eddy current is larger .because eddy currents incresea as resistance decreases.so eddy current damped the oscilation

Brief information about eddycurrents:

Eddy currents (also called Foucault currents[1]) are loops of electrical current induced within conductors by a changing magnetic field in the conductor, due to Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. They can be induced within nearby stationary conductors by a time-varying magnetic field created by an AC electromagnet or transformer, for example, or by relative motion between a magnet and a nearby conductor. The magnitude of the current in a given loop is proportional to the strength of the magnetic field, the area of the loop, and the rate of change of flux, and inversely proportional to the resistivity of the material.

By Lenz's law, an eddy current creates a magnetic field that opposes the magnetic field that created it, and thus eddy currents react back on the source of the magnetic field. For example, a nearby conductive surface will exert a drag force on a moving magnet that opposes its motion, due to eddy currents induced in the surface by the moving magnetic field. This effect is employed in eddy current brakes which are used to stop rotating power tools quickly when they are turned off. The current flowing through the resistance of the conductor also dissipates energy as heat in the material. Thus eddy currents are a source of energy loss in alternating current (AC) inductors, transformers, electric motors and generators, and other AC machinery, requiring special construction such as laminated magnetic cores to minimize them. Eddy currents are also used to heat objects in induction heating furnaces and equipment, and to detect cracks and flaws in metal parts using eddy-current testing instruments.

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